Currently, the structure of known conventional motor-driven stirring blender cup for the household or outdoor use is of somewhat same as disclosed in the U.S. Pat. Nos. 4,435,084 and 5,639,161 and shown in the FIG. 1. All of which, an output shaft 6 driven by the motor M is disposed in the lower section of the blender cup 1, and a propeller 4 is securely linked to said output shaft 6. Wherein, said propeller 4 is directly extended into the inside of the internal chamber 2 to rotationally stirring the liquid or fluid W infused therein; and the power source is the dry battery B of commercial availability. Further, a start switch 7 is set on the handle 3 of said blender cup 1 or somewhere convenient to activate said motor M if it depressed. Via said output shaft 6, the power of said motor M is transferred to said propeller 4 for driving it to rotationally stirring the liquid or fluid W in said internal chamber 2 of said blender cup 1.
However, the same serious drawback exists in both of conventional motor-driven blender cup aforesaid or others in commercial availability: the output shaft 6 of the motor M must pass through the bushing 5 in the base wall under said internal chamber 2 of said blender cup 1; Hence a gap δ will be formed at the contact portion between the circumference of said output shaft 6 and the inner wall of said bushing 5 due to mutual friction (as shown in the magnified view of the FIG. 1), so that the liquid or fluid W to be stirred and blended in said internal chamber 2 will leak and seep into the bottom portion of said blender cup 1 via said gap δ; Before long, it will cause motor M, dry battery B and start switch 7 short circuit or defectively damaged, and result in total malfunction of the blender cup; That is the insoluble drawback and problem exists in all conventional motor-driven blender cup of commercial availability.
Moreover, subject to the inevitable moisture leakage and seepage issue aforesaid, the manufacturer is unable to equip more than two set of propeller 4 in the internal chamber 2 to avoid augmenting the drawback of moisture leakage and seepage; Therefore, the only way for all those current motor-driven blender cups of commercial availability to meet the requirement of better well-mixed is to increase the stirring time with unavoidable side-effect of expediting depletion of the dry battery B relatively, which resulting in more expenditure for consumers to frequently replace said dry battery B; Thus, the mass consumers have to bear the extra cost due to inferior product from careless and unenterprising contrivance of the undutiful manufacturers seems senseless and unreasonable.